cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A088163 Numbers for which rotating one binary place to the right less rotating one binary place to the left is equal to zero.

Original entry on oeis.org

0, 1, 2, 3, 7, 10, 15, 31, 42, 63, 127, 170, 255, 511, 682, 1023, 2047, 2730, 4095, 8191, 10922, 16383, 32767, 43690, 65535, 131071, 174762, 262143, 524287, 699050, 1048575, 2097151, 2796202, 4194303, 8388607, 11184810, 16777215, 33554431, 44739242, 67108863
Offset: 0

Views

Author

Robert G. Wilson v, Sep 13 2003

Keywords

Comments

n is a member iff n is of the form 2^n -1 (A000225) or A000975(2n).

Crossrefs

Programs

  • Mathematica
    f[n_] := FromDigits[ RotateRight[ IntegerDigits[n, 2]], 2] - FromDigits[ RotateLeft[ IntegerDigits[n, 2]], 2]; Select[ Range[33560000], f[ # ] == 0 &]
    (* Or *) Union[ Join[ Table[2^n - 1, {n, 0, 25}], Table[ Ceiling[2(2^n - 1)/3], {n, 2, 24, 2}]]]
    LinearRecurrence[{0,0,5,0,0,-4},{0,1,2,3,7,10},40] (* Harvey P. Dale, Feb 20 2022 *)
  • PARI
    concat(0, Vec(x*(1+x)*(1+x+2*x^2) / ((1-x)*(1+x+x^2)*(1-4*x^3)) + O(x^50))) \\ Colin Barker, May 14 2016

Formula

Numbers n such that A038572(n) - A006257(n) = A088161(n) = 0.
From Colin Barker, May 14 2016: (Start)
a(n) = 5*a(n-3)-4*a(n-6) for n>5.
G.f.: x*(1+x)*(1+x+2*x^2) / ((1-x)*(1+x+x^2)*(1-4*x^3)).
(End)